Cosmopolitan professionals are a common sight on the streets of Shanghai and Beijing. Sleek young men and women sending messages on their shiny new mobile phones, carrying designer handbags on their way to a fashionable entertainment zone.

They are representatives of China's extraordinary achievements in the past 30 years, which transformed an inward-looking culture into one that embraces new ideas and products from abroad. Having had limited consumer options in the past, it is not surprising that the new generation wants to live in a style their parents could not even dream of and adorn themselves with the latest gadgets and fashionable items.

However, while increasing domestic consumption will help the economy to expand, there's always a limit to how much an individual can spend. For most of us, that limit is defined by our monthly salaries. In China, many young working professionals are exceeding that limit and buying things they simply can't afford. This has been fuelled by easy access to credit from an expanding credit card industry - and perhaps encouraged from an early age by their spoiled only-child status.

You would not be able to tell from their consumer items and lifestyles, but many young workers even in the cities do not earn much more than 5,000 yuan (HK$5,800) a month. So common is the phenomenon that they have been labelled the 'Moonlight Clan', a reference to their cycle of spending which does not allow for savings. A recent survey found that 90 per cent of this demographic say they cannot afford to support their parents.

For a society in which the burden of caring for the elderly is expected to be taken up by the children, this pattern of spending could have far-reaching consequences. The one-child policy means the burden of care could fall upon a single member of the family. Ideally, China's economy will eventually spread the wealth to the middle-class and increase average incomes. Meanwhile, the younger generation will need to learn that traditional values of thrift still have some merit today.